We are developing Iron-57 Nuclear Magnetic Resonance (NMR) as an experimental method for use in the Biochemical Sciences. Numerous molecules essential to life are constructed about iron-containing central cores. Among these are hemoglobin, ferridoxin and the cytochromes. To date, no physical chemical methods have allowed direct study of the central metal environment of these proteins. Iron-57 nmr, i.e. the direct detection of the iron nmr signal, is being developed for that purpose. We have recently reported results of an Iron-57 NMR investigation of characteristic relaxation times and chemical shifts of some iron compounds. The data furnished information on the chemical shift range of iron coordinated to nitrogen, substituent effects on Iron-57 chemical shifts, and relaxation mechanisms for Iron-57, and thus provide the basic parameters needed for further development of Iron-57 NMR.